The present invention relates to a pipe holding device that fixes or slidably holds pipes having different diameters.
For example, Japanese Laid-Open Patent Publication No. 2007-79437, Japanese Laid-Open Patent Publication No. 2001-159407, and German Patent Application Publication No. 10,257,515 disclose a pipe holding device of this type. The pipe holding device disclosed in Japanese Laid-Open Patent Publication No. 2007-79437 holds an upper pipe on a lower pipe extending upward from a bass drum. The pipe holding device is provided with a clamp member made of metal, a bolt inserted into a hole of the clamp member, and a T-shaped nut screwed to the bolt. With this configuration, since the clamp member holds the upper pipe by tightening the T-shaped nut, the upper pipe is fixed to the lower pipe. Since holding of the upper pipe by the clamp member is released when loosening the T-shaped nut, the upper pipe can slide with respect to the lower pipe.
The pipe holding device disclosed in Japanese Laid-Open Patent Publication No. 2001-159407 is provided with a holding tool, a bushing made of resin housed in the holding tool, a bolt inserted through both holes of the holding tool and the bushing, and a T-shaped nut screwed to the bolt. With this configuration, when turning the T-shaped nut, since a washer presses end portions of the bushing and the bushing fastens a small diameter pipe, the small diameter pipe is fixed to a large diameter pipe. Since pressing of the bushing by the washer is released when loosening the T-shaped nut, the small diameter pipe can slide with respect to the large diameter pipe.
The pipe holding device disclosed in German Patent Application Publication No. 10,257,515 is provided with a clamp, a bushing made of resin and located inside the clamp, a bolt inserted through a hole of the clamp, and a T-shaped nut screwed to the bolt. With this configuration, when turning the T-shaped nut, since the clamp fastens the bushing from the outside and the bushing fastens a small diameter pipe, the small diameter pipe is fixed to a large diameter pipe. Since fastening of the bushing by the clamp is released when loosening the T-shaped nut, the small diameter pipe can slide with respect to the large diameter pipe.
As described above, the pipe holding device disclosed in Japanese Laid-Open Patent Publication No. 2007-79437 is configured to directly hold the upper pipe by the metal clamp. For this reason, it is possible to sufficiently ensure a fixing force for fixing the upper pipe to the lower pipe, by the rigid, metal clamp. However, since the metal clamp comes into direct contact with the upper pipe, an outer peripheral surface of the upper pipe may be damaged, or when allowing the upper pipe to slide, a harsh metallic sound may be produced. Meanwhile, the pipe holding devices disclosed in Japanese Laid-Open Patent Publication No. 2001-159407 and German Patent Application Publication No. 10,257,515 are configured to directly hold the small diameter pipe by the bushing made of resin. In this case, since the resin has self-lubricating properties, it is possible to allow the small diameter pipe to smoothly slide with respect to the large diameter pipe. However, since the rigidity of the resin bushing is smaller than that of the metal clamp, it is not possible to sufficiently ensure a fixing force for fixing the upper pipe to the lower pipe.